In addition to an interface for a wired connection to an external control device, modern hearing aids also have a transmitting/receiving device for the wireless connection of the hearing aid to the external control device. Within the scope of wireless programming, the hearing aid can also receive programming data from an external programming device via a radio link of this kind. This also permits wireless binaural coupling of hearing aids with which the two hearing aids can be coupled together in such a way that they work as an integrated unit and functions such as volume or program selection are synchronized between the two hearing aids. However, a hearing aid with an integrated receiving device for the wireless reception must be expected to have a higher power consumption. Since, as rule, the hearing aid only has access to its internal power supply, the wireless data transfer inevitably results in a reduced operating time and hence in more frequent battery changes. For this reason, it is desirable to keep the additional power consumption caused by the receiving device as low as possible. In addition, with the wireless programming of hearing aids, it is necessary to prevent illegal programming accesses and possibly to work at a higher data rate than that used in normal operation.